CS 4400 Chapter Notes - Chapter 5: Superkey, Referential Integrity, Data Integrity
24 Dec 2017
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Chapter 5: the relational data model and relational db constraints. Relational model of data is based on concept of relation. Model first proposed by dr. e. f. cobb of ibm research in 1970. Data in each row represents facts referring to a real-world relationship. Column headers signifies the meaning of the data in the column. Each row has a value of a data item that uniquely identifies it. When row-id or sequential numbers are used as keys they are called surrogate or artificial keys. Attribute domain: set of valid values for an attribute. Value derived from appropriate domain n-tuple: tuple consisting of n values. Logical definition: ex) usa phone numbers are the set of 10 digit phone numbers valid in the us. Data-type/format: ex) usa phone numbers (ddd)-ddd-dddd where each d is a decimal digit. Attribute name: designates role played by a domain in the relationship. Ex) domain date can be used for invoice-date and.
